The invention relates to an apparatus for reducing of rubber, in particular scrap rubber, scrap tires, rubber parts and rubber wastes, to particles, the apparatus comprising an inclined pre-cooling tunnel, comprising a conveyor means and adapted to be charged via a feed shaft, a main cooling tunnel, linked to the pre-cooling tunnel by a connection shaft, filled, at least in part, with a cooling medium and provided with a conveyor means and a crusher means downstream of the main cooling tunnel.
The purpose of such a plant, as disclosed, for example, in DE 39 15 984 C1, is to dispose of scrap rubber, namely to recycle it. The problem is that rubber in the form of fully vulcanized caoutchouc is not plastified by heating but becomes charred instead.
Scrap rubber also occurs in large quantities in the form of car tire carcasses which can no longer be retreaded. Such scrap tires present a considerable disposal problem and, in the disposal by incineration generally applied to date, generate a large amount of toxic waste gases which in turn have to be disposed of by suitable filter plants.
A further problem arises from the textile or metallic reinforcements incorporated in the carcasses. Scrap rubber, according to the known process, is to be converted into reusable material by way of granulating and is thus to be reprocessed into a new product. For this purpose, the elastic scrap rubber, with the aid of a cooling medium, namely liquid nitrogen, is cooled down to very low temperatures, approximately -140.degree. C., causing it to embrittle, whereafter it can be ground. A problem of the known process arises from having to cool and embrittle the scrap tires to be reduced right into the innermost region thereof. For this purpose a sufficiently long exposure of the scrap tires to the cooling medium is required. At the same time a satisfactory conveyance of the slowly cooling tires, must be ensured in order to eliminate heating by friction.